Session D06: Progress in Analytical Relativity

Live

I will describe a surprising connection between two longstanding conjectures: cosmic censorship and weak gravity. I will first present a class of counterexamples to (weak) cosmic censorship in anti-de Sitter spacetime. These are solutions in which the curvature grows without bound in a region of spacetime visible to infinity. I will then explain the weak gravity conjecture and show that when it is satisfied, these counterexamples go away. Various generalizations will be discussed with similar conclusions: in almost all cases the weak gravity conjecture removes potential counterexamples to cosmic censorship.   

Live

A growing research program seeks to obtain new results concerning the classical gravitational dynamics of black holes from advanced techniques for computing scattering amplitudes in quantum field theories, having in mind applications in gravitational-wave astronomy. At least perturbatively, a nonspinning black hole is well described by an effective point-particle worldline action coupled with the Hilbert action, and this corresponds to a classical limit of a quantum massive scalar field/particle minimally coupled to gravitons. Effective classical descriptions of spinning black holes seem to similarly correspond to "minimally coupled" higher-spin (indeed infinite-spin) massive fields/particles. I will discuss the nature of this observed but unexplained correspondence, the evidence for it, and its novel results, while pointing out the current frontiers of understanding.   

Not Participating

In this talk, I will describe ongoing work and recent progress using a particularly clean and astrophysically important limit of the two-body problem, that of large mass ratio. This limit accurately describes extreme mass ratio capture systems, anticipated to be an important contributor to the data for future LISA measurements, and has proven surprisingly useful even at mass ratios that are not so large. I will describe the framework that is now being built to rapidly compute leading-order "adiabatic" large mass-ratio waveforms, ongoing work to examine important effects that go beyond this leading order, and recent analyses which indicate that one can extrapolate large mass-ratio results surprisingly far beyond this limit's strict domain of validity.